Question

What can best be inferred about the hind leg bones seen in whales?
Responses
A The hind leg bones of the whales are fossil structures from an extinct ancestor.The hind leg bones of the whales are fossil structures from an extinct ancestor.
B The hind leg bones of the whales are analogous structures to the fins of living fish.The hind leg bones of the whales are analogous structures to the fins of living fish.
C The hind leg bones of the whales are homologous structures to the wings of butterflies.The hind leg bones of the whales are homologous structures to the wings of butterflies.
D The hind leg bones of the whales are vestigial structures that had a function in an extinct ancestor.

Answer 1

D

Whales retain small, internal hind limb bones that are vestigial—remnants of functional hind limbs in their terrestrial ancestors (homologous to other mammalian limbs but no longer used for locomotion).